A source with knowledge of the situation tells PFT that Albert Haynesworth suffered a “bad sprain” of the MCL in the final moments of today’s loss to the Houston Texans.

The exact extent of the injury will not be known until team doctors have the results of an MRI exam, which is scheduled to be conducted on Monday. The injury took place when Haynesworth ended up on the ground with his left leg pinned under a pile of players.

Losing Haynesworth for any time at all would be a significant blow to the Titans. Haynesworth has been a dominating presence in the middle of the Titans’ defensive line this season, and he has a career-high 8.5 sacks.

The Titans host the Steelers next week in a game that could determine home-field advantage throughout the AFC playoffs.